# Effect of advanced pregnancy on intraocular pressure, tear secretion and hemogram values in Holstein cows

## TL;DR

This study examines how advanced pregnancy affects eye pressure, tear production, and blood parameters in Holstein cows.

## Contribution

The study identifies pregnancy-related asymmetry in tear production and hematological changes in cows.

## Key findings

- Pregnant cows showed significant asymmetry in tear production between eyes.
- Pregnancy caused significant changes in mean platelet volume and atypical lymphocyte counts.
- No significant differences were found in intraocular pressure or average tear production between pregnant and non-pregnant cows.

## Abstract

This study investigates how pregnancy influences ocular physiology and hematological parameters in Holstein cows as a topic with limited representation in veterinary research. Thirty clinically healthy cows, aged 2–6 years, were examined and categorized into pregnant (n = 15) and non-pregnant (n = 15) groups. Intraocular pressure (IOP) and tear production (Schirmer Tear Test, STT) were measured bilaterally, and comprehensive blood profiles were evaluated. No statistically significant differences were observed between groups in IOP and mean STT values (p > 0.05); however, a notable asymmetry in tear production was found between the right and left eyes of pregnant cows (p < 0.05), suggesting a localized physiological modulation during gestation. Hematological results revealed significant changes in mean platelet volume (MPV) and atypical lymphocyte percentages and counts (%ALY, ALY) (p < 0.05), highlighting the systemic immune and hematologic adaptations that accompany pregnancy. These findings underscore the importance of recognizing pregnancy-induced physiological shifts in clinical evaluations to avoid misinterpretation of normal adaptive changes as pathological. Future research integrating hormonal profiling could provide deeper insight into the mechanisms driving these alterations.

The online version contains supplementary material available at 10.1007/s11250-026-04957-3.